The present invention relates generally to the field of semiconductor manufacturing. More particularly, the present invention relates to fin field effect transistors and a method for manufacturing the same.
The need to remain cost and performance competitive in the production of semiconductor devices has driven integrated circuits to increased device density. To facilitate the increase in device density, new technologies are constantly needed to allow the feature size of these semiconductor devices to be reduced.
The push for ever increasing device densities is particularly strong in CMOS technologies such as in the design and fabrication of field effect transistors (FETs). FETs are the dominant components of complementary metal oxide semiconductors (CMOS). Scaling FETs to attain higher device density in CMOS results in degradation of short channel effect and/or reliability.
One type of FET that has been proposed to improve short channel effect and facilitate increased or not decrease device density is a fin Field Effect Transistor (“finFET”). In finFETs, the body of the transistor is formed from a vertical structure, generally referred to as a “fin” for its resemblance to the dorsal fin on a fish. The gate of the finFET is then formed on one or more sides of the fin. FinFETs have several advantages, including better current control without requiring increased device size. FinFETs thus facilitate scaling of CMOS dimensions while maintaining an acceptable performance.
FinFETs are generally produced using silicon-on-insulator (SOI) wafers. While the use of SOI wafers provides needed isolation for finFETs, it is not without significant drawbacks. The most compelling drawback of forming finFETs from SOI wafers is the added costs for SOI wafers compared to bulk silicon wafers. For example, SOI wafers can commonly cost two to three times the cost of bulk silicon wafers. This increased cost of SOI wafers, while acceptable for some applications, is prohibitive in others. Additionally, the use of SOI wafers is not compatible with all fabrication processes, such as commonly used SiGe processes.
Thus, there is a need for a method of producing finFETs using the lesser expensive bulk semiconductor substrates.